Sidecar proxy concept (Envoy) in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary role of an Envoy sidecar proxy in Kubernetes?

In a Kubernetes pod, Envoy is often deployed as a sidecar proxy. What is its main function?

A To handle network traffic between microservices, providing features like load balancing and security.

B To store persistent data for the application running in the pod.

C To schedule pods across different nodes in the cluster.

D To monitor CPU and memory usage of the pod.

💡 Hint

Think about what a proxy does in networking and how Envoy fits into microservice communication.

Envoy acts as a network proxy that manages and controls traffic between microservices, enabling load balancing, security, and observability.

💻 Command Output

intermediate

Output of Envoy sidecar proxy logs in Kubernetes

You run kubectl logs -c envoy to check the Envoy sidecar logs. What kind of information will you most likely see?

A Kubernetes scheduler decisions and pod placement logs.

B Application business logic errors and stack traces.

C Details about incoming and outgoing HTTP requests, connection status, and errors.

D Database query results and cache hits.

💡 Hint

Envoy is a proxy; what kind of logs would a proxy generate?

Envoy logs show network traffic details such as HTTP requests, connection status, and any proxy-related errors.

❓ Configuration

advanced

Correct Envoy sidecar container configuration snippet in a Kubernetes pod spec

Which container spec snippet correctly configures Envoy as a sidecar proxy in a Kubernetes pod?

A

containers:
  - name: envoy
    image: envoyproxy/envoy:v1.22.0
    ports:
      - containerPort: 15001
    args: ["-c", "/etc/envoy/envoy.yaml"]

B

containers:
  - name: envoy
    image: envoyproxy/envoy
    ports:
      - containerPort: 8080
    command: ["/bin/bash"]

C

containers:
  - name: envoy
    image: envoyproxy/envoy:v1.22.0
    ports:
      - containerPort: 80
    args: ["--help"]

D

containers:
  - name: envoy
    image: envoyproxy/envoy:v1.22.0
    ports:
      - containerPort: 443
    args: ["-c", "/etc/envoy/config.yaml"]

💡 Hint

Look for the correct image tag, port, and config file argument.

Option A uses a specific Envoy version, the typical admin port 15001, and points to the standard config file path.

❓ Troubleshoot

advanced

Troubleshooting Envoy sidecar proxy failing to route traffic

You notice that traffic is not reaching your microservice through the Envoy sidecar proxy. Which of the following is the most likely cause?

A The pod's CPU limit is too low, causing Envoy to crash.

B Envoy configuration file has incorrect cluster or listener settings causing routing failure.

C Kubernetes node is out of disk space, preventing pod scheduling.

D The microservice container image tag is outdated.

💡 Hint

Think about what controls Envoy's routing behavior.

Envoy relies on its configuration file to route traffic correctly. Incorrect cluster or listener settings will cause routing failures.

🔀 Workflow

expert

Order the steps to deploy Envoy as a sidecar proxy in a Kubernetes pod

Arrange the following steps in the correct order to deploy Envoy as a sidecar proxy in a Kubernetes pod.

A 2,1,3,4

B 3,2,1,4

C 1,3,2,4

D 1,2,3,4

💡 Hint

Think about preparing config first, then pod spec, then deployment, then verification.

You first create the Envoy config, then add the sidecar container to the pod spec, deploy the pod, and finally verify the sidecar is working.